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N-Acetylcysteine 25mg/ml eye drops

‘Off the shelf’ anti-collagenase

  • Ready-made, sterile formulation.

  • Convenient for prescriber, pet owner and patient

Easy storage

  • No need to refrigerate

  • 3-year unopened shelf life (7 days opened)

5ml bottle with easy applicator nozzle

  • Simple and consistent dosing

  • Apply 2 drops, 3-4 times daily


Find out how Stromease fits into your treatment regime…

Download our newly revamped corneal ulcer treatment guideline (veterinary professionals only).

Download the guideline now

How does Stromease work?

N-Acetylcysteine (also known as NAC, Acetylcysteine or N-Acetyl-L-cysteine), is widely used in human and veterinary medicine for its anti-collagenase, mucolytic and antioxidant properties.1.2

N-Acetylcysteine inhibits collagenases irreversibly by reducing disulphide bonds and chelating calcium and zinc, co-factors required by MMPs(Matrix Metalloproteinases).

MMPs are proteinase and collagenase enzymes that are present naturally within the tear film and cornea. Under normal circumstances, MMPs help to maintain corneal homeostasis and exist in fine balance with their inhibitors.3 However, MMPs are upregulated in ocular surface diseases4 (such as, corneal ulceration), and also secreted by some invading bacterial species.

As MMP activity increases, inhibitor molecules may become overwhelmed, which can lead to rapid corneal melting and ocular perforation.  Although MMPs play a role in initial corneal wound healing, down-regulation is necessary to prevent corneal digestion and allow corneal wound healing.2

  1. Tenório, M.C. dos S., Graciliano, N.G., Moura, F.A., Oliveira, A.C.M. de, Goulart, M.O.F., (2021). N-Acetylcysteine (NAC): Impacts on Human Health. Antioxidants 10, 967.
  2. Stromease SPC
  3. Hartley, C. (2021). Outcomes of treatments for keratomalacia in dogs and cats: a systematic review of the published literature including non-randomised controlled and non-controlled studies. Journal of Small Animal Practice 62, 840–849
  4. Sakimoto, T., Shoji, J., Kanno, H., & Sawa, M. (2004). Gelatinase expression in ocular surface disorders. Japanese journal of ophthalmology, 48(1), 17–22.

Stromease 25 mg/ml eye drops, solution for dogs and cats contains Acetylcysteine. Legal category POM-V. For the supportive treatment of corneal ulcers in dogs and cats. Please refer to the product packaging and leaflets for information about side effects, precautions, warnings and contraindications.

Use medicines responsibly. For more information, please view the full SPC or contact TVM UK on 0800 0385868 TVM-UK Animal Health Ltd, Kirtlington Business Centre, Slade Farm, Kirtlington, Oxfordshire, UK. OX5 3JA.